Modification in photovoltaic and photocatalytic properties of bismuth ferrites by tailoring band-gap and ferroelectric properties

Abstract

Bismuth ferrite has recently been extensively studies as potential material for photovoltaic and photocatalytic applications as it provides wide opportunity to tune band-gap by site engineering with suitable elements. Further, this doping modified the optical and ferroelectric properties of bismuth ferrite for the applications. Rare-earth (Gd) and transition-element (Mn, Co and Cr) co-doped samples of bismuth ferrite have been synthesized by the sol-gel technique at low temperature. Structural characterization using X-ray diffraction reveals a phase transformation from rhombohedral to orthorhombic with co-doping in pure BFO sample. A reduction of grain size for doped bismuth ferrites samples is observed in SEM analysis. The dielectric properties get enhanced with co-doping due to decrease in the Fe2+ ions and oxygen vacancies. Increase in the remnant polarization was obtained in doped BFO samples and maximum Pr∼1.615μC/cm2 for Gd doped BFO sample. Decrease in band-gap values with doping has been observed from (2.35–1.90 eV). Power conversion efficiency has been calculated with doping of different substances which results in improved photovoltaic properties with respect to pure BFO (η% ∼0.00039–0.026). Also, photocatalytic studies have been done for all the samples of BFO. Enhanced values of photocatalytic efficiency (η% ∼90.89–96.08) has been observed with co-doping of rare earth and transition elements in bismuth ferrites. Thus, co-doping of rare-earth and transition-element in bismuth ferrite can improve multiferroic, ferroelectric, photovoltaic and photocatalytic properties for different applications.